1. Field
Exemplary embodiments of the invention relate to electrochemical devices including electrode assemblies, and more particularly, to flexible electrochemical devices in which a plurality of electrode assemblies is electrically connected to each other so that the flexible electrochemical devices may be repeatedly bent.
2. Description of the Related Art
Secondary batteries are electrochemical devices that are manufactured to be charged and discharged, unlike primary batteries that cannot be charged. The secondary batteries are widely used in a field of high-tech electronic devices, such as cellular phones, notebook computers, and camcorders.
In particular, lithium secondary batteries have an advantage of higher voltages than those of nickel-cadmium batteries or nickel-hydrogen batteries that are widely used for portable electronic equipment power supply, and an advantage of high energy density per unit weight, for example. Therefore, the demand for lithium secondary batteries is increasing. In the lithium secondary batteries, a lithium-based oxide is mainly used for a cathode active material, and a carbon based material is mainly used for an anode active material. In general, the lithium secondary batteries are classified into liquid electrolyte batteries and polymer electrolyte batteries according to a type of an electrolyte. Batteries that use a liquid electrolyte are referred to as lithium ion batteries, and batteries that use a polymer electrolyte are referred to as lithium polymer batteries. Also, the lithium secondary batteries are manufactured in various shapes such as a cylindrical battery, a prismatic battery, and a pouch-type battery. Conventionally, jelly-roll type electrode assemblies in which a separator is inserted between a positive electrode plate and a negative electrode plate and the positive electrode plate and the negative electrode plate are rolled in a spiral form together with the separator, or stack-type electrode assemblies in which a positive electrode plate and a negative electrode plate are repeatedly stacked and a separator is inserted between the positive electrode plate and the negative electrode plate, are widely used in the lithium secondary batteries.
As attention for flexible electronic devices that can be flexibly bent is increasing, research into manufacturing flexible batteries that can be used in flexible electronic devices is increasing.